With BSSD technology and an approach that favors animal welfare, the Licevax2 project seeks to transform immunization into salmon farming, reducing animal stress and strengthening fish health. The project funded by FONDEF IT marks a milestone in the application of biotechnology in Chilean aquaculture.
In salmon farming, the use of injectable vaccines is a common practice for disease prevention. However, these vaccines have an important limitation: they are usually applied early in development, usually in the hatchery, before the fish are transferred to sea cultivation. Although there is the possibility of a revaccination, this process is complex once the fish are at sea, since it implies manipulation of fish, which generates high levels of stress, negatively affecting their well-being.
The oral vaccine emerges as an innovative solution to this challenge. It consists of incorporating the antigen directly into the food, allowing the fish to be immunized without the need for physical intervention. This approach facilitates administration in more advanced stages of the production cycle. In addition, by reducing stress and mortality associated with injectable treatments, the oral vaccine strengthens the ability of the fish to cope diseases, contributing to more sustainable and efficient production.
In this line of action, the Research Associate of the Genomic Aquaculture Line of the Interdisciplinary Center for Aquaculture Research (INCAR), Dr. Valentina Valenzuela-Muñoz, awarded FONDEF IT “Licevax2: oral vaccine based on bssd technology for the control of caligidosis in Atlantic salmon”.
The project has the Deputy Director of INCAR Center, Dr. Cristian Gallardo-Escarate, as Alternate Director, and with the participation of RP1 researchers Dr. Yeny Leal-Acosta, Dr. Diego Valenzuela-Miranda and Dr. Antonio Casuso. In addition, AQUATRECK, a new generation aquaculture pharmaceutical company, incorporated in O Porriño, Pontevedra, Spain, participates as an associated institution, whose aim is to reinvent health management. to support sustainable growth in the aquaculture industry.
“In the search for new strategies for the control of caligidosis, we have two antigens identified in Caligus, the parasite affecting salmon. These antigens have been repeatedly evaluated by us as injectable vaccines, demonstrating high efficacy by significantly reducing the parasitic load. However, because they are recombinant proteins, their use in the salmon industry has disadvantages, since they are vaccines with high production costs, involve fish management and are difficult to use in stages. advanced productions, ” explained Dr. Valenzuela-Muñoz.
To overcome this limitation, the INCAR Center team opted for Bacillus subtilis Spore Surface Display (BSSD) technology. This technique allows to express proteins on the surface of the spores of Bacillus subtilis, bacteria that, under stressful conditions, form spores as a survival mechanism. “Spores are an attractive vehicle for antigens because they are highly resistant to stress conditions, as well as stimulating the mucosal response, and are easy to produce and scale,” explains the Project Director.
This property is especially useful in oral administration through food, as the pellet manufacturing process includes high-temperature stages such as oiling. In this way, spores give stability to the antigen during this process, allowing it to reach the fish intact.
BSSD technology
“BSSD technology represents a cutting-edge innovation that has not yet been used in animal health in Chile. So far, studies have focused mainly on human vaccines, which opens a unique opportunity to apply this approach to aquaculture and move towards more efficient and less invasive immunization systems,” said Dr. Valentina Valenzuela-Muñoz
This technology has already been evaluated at the experimental level and, during the execution of this project, the technology in relevant environment will be evaluated for 2 years, determining the best concentration of spores to be delivered orally to the fish and to generate the expected response against Caligus. This also includes tests to determine optimal antigen proportions, in order to identify the combinations that best reduce the load Parasite.
Once the most promising formulations are defined, a second phase will be carried out in ponds, this time with successive infestations of Caligus. The objective will be to see whether long immunization — for at least three months — is achieved or whether there is a cumulative effect over time. Researchers argue that the mechanism of action could be related to changes in the mucus of the fish, which would affect the parasite's ability to infection.
“Ended the stage in the relevant environment, the project will advance towards a test in real conditions of cultivation at sea, where the fish will be fed with the product developed and exposed to the corresponding regime in the sea phase of salmon cultivation,” added Dr. Valenzuela-Muñoz.
For the INCAR team, the formulation and award of FONDEF IT represents a collective triumph, since this line of competition of the ANID aims to finance research and development projects based on hypotheses of application of a technology, product or service, and that, within two years, point to its validation through advanced prototypes and, finally, facilitate its transfer to the industry, the market or the society, including the design of a business model.
This is why scaling will allow progress to be made in the validation and marketing potential of a product with a high impact on the aquaculture sector.
